1. Field of the Invention
The present invention relates to a wearing element for a comminuting machine whose rotating knife head includes a support disc, a support ring arranged coaxially to the support disc and knife carriers which are distributed uniformly over the circumference and are arranged axially between the support disc and the support ring. The wearing element is composed of a plate having a certain thickness and the shape of a ring sector. The plate covers the inner periphery of the outer side of the support ring and has in the area of the gap between two knife carriers an inclined surface extending over the thickness of the wearing element toward the support ring. The wearing element is an element which is subject to wear during normal use.
2. Description of the Related Art
Comminuting machines of the above-described type, as they are known, for example, from DE 35 05 077 C2, are suitable, among other purposes, for comminuting long timber. The long timber to be cut is cyclically moved in the axial direction up to a stop plate in the interior of the cutting space of a comminuting machine. While the portion of the long timber extending out of the cutting space is secured, a rotating knife head moves during each work cycle transversely of the axial direction of the timber and shortens the timber over a length which corresponds to the depth of the cutting space. Subsequently, the knife head is returned into the initial position, the pieces of timber are once again moved up to the stop in the cutting space and a new work cycle begins.
In machines of this type, the knife head which defines the cutting space is composed of a support disc, a support ring arranged coaxially to the support disc and knife carriers arranged between the support disc and the support ring. The knife carriers are uniformly distributed over the circumference of the knife head, wherein an axial gap is defined as a result of a predetermined distance between the individual knife carriers. The chips are moved from the cutting space and the area of the knife head through this gap.
In order to be capable of comminuting also the portion of the timber extending into the cutting space, it is necessary that the knives held in the knife carriers extend at least up to the outer side of the carrier ring. If this were not the case, the support ring would contact the timber with its inner surface and would prevent a transverse movement of the knife head. A problem in this connection is the removal of the chips produced in the area of the support ring. In order to ensure that the chips are conducted into the interior of the comminuting machine, the inner surface of the support ring is provided in the gap area between two knife carriers over the entire width thereof with an inclined surface portion extending toward the interior of the comminuting machine. This inclined surface portion forms a duct through which the chips are conducted toward the gap between two knife carriers.
When such comminuting machines are operated, significant wear phenomena can be observed in the area of the duct which makes it necessary to prematurely exchange the support ring. This wear is due to impurities in the material to be comminuted in the form of water, sand and dirt which over time lead to crack-like erosions and impair the strength of the support ring as a result.
In order to prevent these problems, plate-shaped wearing elements have been arranged at the inner circumference of the outer side of the support ring, wherein these plate-shaped wearing elements have at the location of the duct an inclined surface portion and which over the thickness thereof protect a portion of the inner surface of the support ring. This measure has turned out not to be sufficient because wear phenomena still occur at the non-protected portion of the inner surface of the support ring and at the inner side thereof.